This might be a tangent to the original topic, but on the writing side... my big thing with conversation is to solve as much of the pacing in the dialog as possible. I like to condense my text, and try to reveal as much as I can without actually saying it.
For example, if Bob says "Why are you going into town? It's only Tuesday." one might be tempted to fill his pal Amos' dialog with some kind of exposition, like "I'm getting horseshoes. Our blacksmith has taken ill, so I've gotta head into town if I'm gonna get the old mare... blah blah blah". Boring.
Why not cut out the blacksmith and instead do some characterization? For instance...
Bob "Now where are you headed off to? It's only Tuesday"
Amos "Don't you worry, I'm only going for horseshoes, Bob. The tavern don't open until sundown, and I'll be back long before that. You can count on me."
Bob "Yeah, well. You'd better be."
And then maybe revise down to...
Bob "It's Tuesday, Amos. Why're you saddlin' up?"
Amos "Just goin' for horseshoes, Bob. Tavern don't open 'til sundown, an' I'll be back long before."
Bob "You'd better be."
And so on. Now... I haven't said anything about their occupation, their history or their problems, but there are several implications in play. I think that's more fun.